Answer:
C. 3 × (54 + 21) < 6 × (54 + 21)
Step-by-step explanation:
This is because, the factor 3 in from of the elements in parentheses on the left hand side is less than the factor 6 in from of the elements in parentheses on the right hand side. Thus, the product on the left hand side is less than the product on the right hand side, since the sum in parentheses on both sides are the same.